1. Field of the Invention
This invention is related to powdered milk solids having a specific free fatty acid profile that may be used to prepare chocolate having a flavor profile with a developed milk character, which may be described as having a cheesy, soured and perceived xe2x80x9csoapyxe2x80x9d character. The invention is also directed to a method of preparing such powdered milk solids by enzymatic modification, a method of preparing chocolate using the powdered milk solids and the chocolate prepared thereby.
2. Related Background Art
It has long been known that the flavor profile of milk chocolate can vary. Many attempts have been made to control this variability and consistently achieve a particular flavor profile. For example, U.S. Pat. No. 1,966,460 is directed to the preparation of milk-containing products, such as milk chocolate, with a distinctive milk or butter flavor by adding lipolyzed butter fat to the milk solids used in the milk-containing product. The success of this method, however, is challenged in U.S. Pat. No. 2,794,743 which alleges that the process of U.S. Pat. No. 1,966,460 resulted in xe2x80x9coffxe2x80x9d flavors.
This problem is alleged to have been overcome in U.S. Pat. No. 2,794,743 by using an enzyme composition having both lipolytic and proteolytic qualities for modifying milk powder. In particular an enzyme powder is employed that is said to produce relatively higher levels of C6 and higher fatty acids compared to the level of C4 and lower acids, but where the level of C4 free fatty acid is greater than the other lower fatty acids. The enzyme powder is added to whole milk powder in amounts up to 50%, preferably 1% to 5%, to obtain milk chocolate with a modified flavor. The exemplified milk powders all have a C4 to C6 and higher fatty acid percentage ratio greater than 1:2.
U.S. Pat. No. 2,638,418 is directed to the preparation of a milk product that imparts a desirable flavor to milk chocolate by hydrolyzing milk fat and reducing two of three categories of free fatty acids. The categories are described as volatile water-soluble free fatty acids, volatile water-insoluble free fatty acids and non-volatile water-insoluble free fatty acids. It is stated that the first two categories of free fatty acids should be present in slight excess to the free fatty acids of the third category. There is, however, no disclosure of the specific fatty acid profile of the milk fat. Moreover, in tests conducted by the present inventors it was found that under certain high temperature and pressure conditions (e.g. 140xc2x0 C. and 47 psi) the ratio of C4:C14 in milk powder actually increased.
U.S. Pat. No. 2,835,593 describes the preparation of a base flavor by enzymatic hydrolysis of milk fat and protein. The base flavor may be used to prepare an artificial chocolate or to modify the flavor of chocolate. It is alleged that the base flavor contains buttery aromas suggestive of the cowy butyral character desired in milk chocolate. The specific fatty acid profile of the flavor is not disclosed.
Acceleration of the lipolysis in milk powder for use in milk chocolate is described in U.S. Pat. No. 4,081,568. The technique is performed by adjusting the pH of the mixture of ingredients used to produce milk chocolate. The lipolysis generally results in 2.4 to 2.5% by weight of free fatty acids based on total fat. Again there is no specific disclosure of the free fatty acid profile.
A crumb-flavored milk chocolate composition prepared by adding fatty acids to milk powder at a temperature below the melting point of the fatty acids and then using the mixture in the manufacture of milk chocolate is described in U.S. Pat. No. 5,393,538. The product may also be prepared by lipolysis of the milk powder to preferentially produce long chain fatty acids.
Milk solids powders that have the specific free fatty acid profile described herein and that consistently provide the desirable developed milk flavor provided for by the present invention in the production of chocolate are not disclosed or suggested in the above-noted references. The phrase xe2x80x9cdeveloped milk flavorxe2x80x9d as used herein means a chocolate that organoleptically may be described as having aromatic characteristics of fermented and enzymatically altered milk products such as cheese and/or sour aromatic associated with xe2x80x9cmilk bottlexe2x80x9d odor. Aromatic sour is associated with fermented and enzymatically altered milk products such as yogurt, sour cream and buttermilk. Accordingly, a milk solids powder that would consistently provide such developed milk flavor to chocolate would be highly desirable.
This invention is related to a powdered milk solids that may be used in the preparation of chocolate, most preferably milk chocolate, to provide a product having a desirable developed milk character. In particular, the powdered milk solids of this invention has a free fatty acid profile wherein the weight ratio of butyric acid (C4) to myristic acid (C14) is equal to or less than 1:2, preferably in a range of 1:2 to 1:10,000, more preferably 1:2.5 to 1:100, even more preferably 1:3 to 1:10 and most preferably 1:3 to 1:6.
The invention is also related to the methods of preparing the powdered milk solids having the above described fatty acid profile. This can be achieved by several different methods. For example, the milk powder may be prepared by adding the desired fatty acid(s) to a conventional untreated milk and drying the same to obtain a milk powder having the required C4 to C14 fatty acid profile. Alternatively, the desired fatty acids may be added at the preferred levels indirectly to any of the chocolate ingredients contained in a chocolate or coating formulation or directly into a liquid finished chocolate product. Addition in this manner is possible with careful addition of the fatty acids and with sufficient blending to assure proper dispersion either to a liquid or dry powder chocolate ingredient. Some fatty acids are volatile components. As such overheating and volatilization of these compounds may result in loss of the flavorants. Dispersion may be carried out using high shear mixers, during batching, conching, liquefaction or standardizing using all known conventional blending equipment. Fatty acids as described herein may be derived from any known means. Typically, fatty acids may be sourced from natural sources via extraction or synthetically produced by enzyme addition or chemical means.
In another embodiment, the milk powder of this invention can be prepared by treating a conventional enzymatically treated milk powder with vacuum to reduce the C4 concentration to achieve the desired C4 to C14 weight ratio. Yet another manner of preparing the milk powder of this invention includes enzymatically modifying a liquid milk to directly obtain a milk having the required C4 to C14 ratio. As used herein, the phrase xe2x80x9cliquid milkxe2x80x9d includes milk, reconstituted milk, partially reconstituted milk, evaporated milk, condensed milk, recombined milk, i.e., milk reassembled from milk components, skim milk containing one or more of milk fat, anhydrous milk fat, milk fat equivalents and butter, and mixtures thereof. It may also be possible to spray dry a cultured milk to obtain the powdered milk solids of the invention.
Yet another embodiment of this invention includes enzymatically treating milk fat, anhydrous milk fat or butter to achieve the desired weight ratio of C4 to C14 or alternatively to remove undesirable fatty acids through steam distillation to achieve the desired C4 to C14 weight ratio. The resultant milk fat or butter may be added to the admixture used to prepare chocolate so as to obtain a chocolate having the required C4 to C14 weight ratio.
Yet another embodiment of this invention is directed to the method of preparing a chocolate having developed milk character by mixing (i) the powdered milk solids of this invention, (ii) optionally, but preferably, cocoa butter, (iii) cocoa solids and/or chocolate liquor and (iv) sugar. If desired, the chocolate prepared thereby may also include milk and/or milk solids that have not been enzymatically modified so long as the powdered milk solids of this invention are present in an amount effective to impart a developed milk character to the chocolate.
A further embodiment of this invention is directed to a method of preparing a chocolate having developed milk character comprising the steps of: (i) admixing a liquid milk with at least one of sugar, chocolate liquor, cocoa solids or cocoa butter to form a liquid chocolate precursor ingredient; (ii) modifying the liquid chocolate precursor ingredient to achieve a C4 to C14 ratio equal to or less than 1:2; (iii) drying the liquid chocolate precursor ingredient; and (iv) preparing the chocolate with the dried chocolate precursor ingredient. The method of modifying the liquid chocolate precursor ingredient may be performed using any of the fatty acid profile modification techniques described herein. The step of drying is preferably spray drying. Preferably, sugar and/or chocolate liquor are added to liquid milk to form the liquid chocolate precursor ingredient. After drying, any additional ingredients desired, including any ingredients used to form the liquid chocolate precursor ingredient, are added to the dry chocolate precursor ingredient to complete the chocolate.
This invention provides powdered milk solids which may be advantageously used to produce chocolate having a desirable developed milk character. The developed milk character may be described through sensory evaluations as providing a soapy, and even cheesy flavor profile. Most preferably the chocolate prepared using the powdered milk solids of this invention is a milk chocolate. Commercially available milk chocolate exhibiting such a flavor profile is well known. It is not believed, however, that powdered milk solids are used in the production of that milk chocolate. Significantly, the powdered milk solids of this invention provides one the ability to consistently obtain a chocolate having a developed milk character.
The consistency of the flavor profile achieved using the milk powder of this invention in the preparation of milk chocolate is dependent upon the free fatty acid profile of the milk solids used in the chocolate. In particular, it has been discovered that milk chocolate having a developed milk character can be produced using powdered milk solids having a free fatty acid profile wherein the weight ratio of butyric acid (C4) to myristic acid (C14) is equal to or less than 1:2, preferably the weight ratio is in a range of 1:2 to 1:10,000, more preferably 1:2.5 to 1:100, even more preferably 1:3 to 1:10 and most preferably 1:3 to 1:6.
This can be achieved by several different methods. For example, the milk powder may be prepared by adding the desired fatty acid(s) to a conventional untreated milk and drying the same to obtain a milk powder having the required C4 to C14 fatty acid profile. Alternatively, the desired fatty acids may be added at the preferred levels indirectly to any of the chocolate ingredients contained in a chocolate or coating formulation or directly into a liquid finished chocolate product. Addition in this manner is possible with careful addition of the fatty acids and with sufficient blending to assure proper dispersion either to a liquid or dry powder chocolate ingredient. Some fatty acids are volatile components. As such overheating and volitization of these compounds may result in loss of the flavorants. Dispersion may be carried out using high shear mixers, during batching, conching, liquefaction or standardizing using all known convention blending equipment. Fatty acids as described herein may be derived from any known source. Typically, fatty acids may be sourced from natural sources via extraction or synthetically produced by enzyme addition or chemical means.
Chocolate as defined herein may be a standardized chocolate such as sweet, mixed dairy, skim milk, or a non-standardized product such as compound coatings which contain vegetable fats replacing some or all of the cocoa butter.
The concentration of the fatty acids in the milk powder of this invention may vary, so long as the required ratio of butyric acid to myristic acid is met. For example, if the dairy component of a chocolate is derived solely from the milk solids of this invention then the concentration of the fatty acids need not be as high as would be required where only a portion of the dairy component of a chocolate was derived from the milk solids of this invention. Generally, the concentration of free fatty acids found in the milk solids of this invention will range as follows:
If the milk solids of this invention is the predominant dairy component in the chocolate then the concentration of the fatty acids will generally be toward the lower end of the above-described ranges. However, if only a portion of the dairy component of the chocolate is provided by the milk solids of this invention, e.g. 10%, then the concentration of free fatty acids in the inventive milk solids will generally gravitate towards the higher end of the above-described ranges.
The powdered milk solids may be prepared in any manner that provides a powdered milk solids with a C4 to C14 weight ratio equal to or less than 1:2. One technique to prepare the powdered milk solids of this invention comprises the step of adding an effective amount of myristic acid (C14) to untreated liquid milk to achieve a C4 to C14 weight ratio equal to or less than 1:2. Conventional enzyme treated liquid milk generally has a C4 to C14 weight ratio of about 1:1. The amount of myristic acid necessary to achieve the desired ratio can be readily ascertained by analytical analysis of the untreated liquid milk. The liquid milk containing the additional myristic acid is then dried using conventional drying techniques, such as spray drying or freeze drying, to result in the powdered milk solids of this invention.
Another technique for preparing the powdered milk solids of this invention includes first using a conventional enzymatic modification method on liquid milk. Such known enzymatically treated liquid milk have C4 to C14 ratios greater than those of the present invention. Exemplary enzymatically treated powdered milks include NDF(trademark) Kosher Whole Milk Flavor (SKW Biosystems, Waukesha, Wis.) and NATURETONE 3968 (Kerry Inc., Beloit, Wis.).
The enzymatically modified liquid milk or powdered milk is then further treated to reduce the C4 fatty acid level to achieve the above-described free fatty acid profile. This further treatment may include, for example, the use of vacuum-techniques well known to those skilled in the art to draw off the more volatile C4 fatty acid in a greater percentage than the C14 fatty acid. The powdered milk solids of this invention are recovered from the modified liquid milk by well known drying techniques, such as spray drying or freeze drying.
Another method of this invention is directed to preparing the milk powder of this invention by enzymatically modifying a liquid milk to directly obtain a milk having the required C4 to C14 ratio. Various microbial cultures may be used for enzymatically modifying liquid milk in the methods of this invention. Generally such microbial cultures may be sourced from food grade microbial genuses such as, for example, Mucor variants, Rhizopus variants, Aspergillus variants, Candida variants and Penicillin variants. More specifically exemplary variants include Mucor javanicus, Rhizopus oryzae, Aspergillus niger, Candida rugosa and Penicillin roqueforti. It is also possible to enzymatically modify milk using food grade enzymes sources from animals such as edible forestomach tissue of calves, kids or lambs or from animal pancreatic tissue.
Yet another embodiment of this invention is directed to a method of preparing chocolate, most preferably milk chocolate, using the powdered milk solids having the free fatty acid profile described herein in an amount effective to provide the milk chocolate with a developed milk character. This method of preparing chocolate comprises mixing sugar, optionally, but preferably, cocoa butter, cocoa solids and/or chocolate liquor and the powdered milk solids of this invention. If desired unmodified milk solids or modified milk solids having the C4 to C14 weight ratio greater than 1:2 may be used in combination with the milk solids of this invention in the method of preparing chocolate so long as the resulting chocolate maintains a C4 to C14 weight ratio equal to or less than 1:2, and preferably in a range of 1:2 to 1:10,000, more preferably 1:2.5 to 1:100, even more preferably 1:3 to 1:10 and most preferably 1:3 to 1:6. This C4 to C14 weight ratio may also be obtained by adding myristic acid directly to the admixture of ingredients used to prepare chocolate.
It is also possible to prepare a chocolate according to the method of this invention using enzymatically treated milk fat, anhydrous milk fat or butter with the desired ratio of C4 to C14. Milk fat, anhydrous milk fat or butter having the desired ratio of C4 to C14 prepared by removing undesirable fatty acids through steam distillation may also be employed. These components may be used alone or in combination with any other components in the chocolate prepared according to this invention so long as the required C4 to C14 ratio is obtained in the resulting chocolate. It should also be readily apparent that the process of this invention also includes reconstituting a milk powder, either wholly or partially, treating the reconstituted milk powder to achieve the desired ratio of C4 to C14 and then drying the treated reconstituted milk powder to form the powdered milk solids used in the preparation of chocolate.
Another embodiment of this invention is directed to the chocolate prepared by the above-described methods of this invention. Chocolates can be manufactured using the powdered milk solids of this invention over a wide range of potential ingredient usage levels that encompass the following ranges:
Other suitable ingredients can be added for desired flavor and functionality. Once the chocolate components have been admixed, forming the chocolate is well within the knowledge of those skilled in the art via such known techniques as conching and refining the chocolate components.
The chocolate of this invention will have a C4 to C14 weight ratio equal to or less than 1:2, and preferably in a range of 1:2 to 1:10,000, more preferably 1:2.5 to 1:100, even more preferably 1:3 to 1:10 and most preferably 1:3 to 1:6. Generally, the chocolate of this invention will contain at least 35 mg of butyric acid per kilogram of chocolate and at least 70 mg of myristic acid per kilogram of chocolate, as well as meeting the weight ratio profile defined above. The amounts of milk powder, sugar, cocoa butter and cocoa solids found in the chocolate of this invention has been previously described in the method used to prepare the chocolate.
A chocolate of this invention having about 12% whole milk solids (including nonfat solids and milk fat) will generally have a concentration of free fatty acids as follows:
While the manipulation of butyric acid and myristic acid have been described in detail herein, one should recognize that other fatty acids, such as caproic, caprylic, capric and lauric acid, may be added or reduced in the milk powder or chocolate of this invention to achieve a desired concentration and a product with a developed milk character.
The chocolate of this invention prepared using the powdered milk solids of this invention may be distinguished from chocolate prepared with liquid milk by the crystal structure of the lactose in the chocolate. Chocolates prepared via a wet milk system show various forms of re-crystallized alpha mono-hydrate lactose, primarily in cubed, partial cube or partial wedge configuration when viewed using polarized light microscopy. This crystalline form of lactose is substantially absent in chocolate prepared using the powdered milk solids of this invention. The chocolate of this invention may also be differentiated from chocolate prepared with liquid milk by the crystal structure of sucrose in the chocolate. Chocolate prepared using liquid milk will contain re-crystallized sucrose having a monoclinic structure while the sucrose in the chocolate of this invention will contain predominantly fractured crystal sucrose. This difference in sugar crystal morphology may also be evaluated by using microchemical techniques that include photomicroscopy analysis involving birefringence and retardation spectra.
More particularly, sucrose and lactose occur primarily in two solid phase states. These consist of two distinctly different formations and are defined by the packing structure of the unit cells. One phase state is crystalline, which exhibits uniform packing of the crystal lattice. The other solid phase condition is amorphous; in which the unit cells are randomly aligned forming a glassy state lattice. Sucrose, assuming the supporting conditions are available, forms a well-defined monoclinic crystal formation. Under less ideal crystal growth conditions, sucrose will form cubes or partial cubes, but are still crystalline based on the spatial arrangement of the unit cells. These monoclinic or cubed structures can be identified using cross-polar light microscopy (CPLM) techniques and exhibit unique birefringence and retardation [optical density] characteristics under cross-polar light. Lactose will also form discrete crystals in the form of wedge or tomahawk like shapes under ideal conditions and partial wedges or cubes under poor conditions. Due to these differences in molecular densities, shape and optical rotation of crystalline sucrose and lactose, micro-chemical and morphological characterization using CPLM techniques can identify these compounds and their structures very readily. Amorphous sugars, [sucrose, lactose] due to the randomness or order of their unit cells, exhibit different birefringence characteristics than their crystalline forms. Sucrose and lactose will form a glass or amorphous structure if the moisture level is high enough to support dissolution. The release of water and small amounts of energy in the form of heat [latent heat of crystallization] occur during glassy state to crystalline transitions.
In addition to the CPLM techniques described above, differential scanning calorimetry (DSC) can differentiate between crystalline and amorphous sugars. A shift in endothermic response occurs when amorphous sugars are pushed through their glass transition [Tg] temperature and exhibits exothermal response during recrystallization. These glass transition and recrystallization events occur at different temperatures for sucrose and lactose depending on Aw or sorption state. Quantitative levels of amorphous sucrose will exist in wet milk and wet system type processes [reconstituted], and will be essentially non existent in dry system processes.
In a wet milk process, liquid whole milk or sweetened condensed milk is condensed by an evaporation process driving off moisture by heat and sometimes vacuum. Sucrose [crystalline] and possibly chocolate liquor is added to this process to facilitate drying, flavor and recipe development. Saturation or super saturation of the milk/sugar solution occurs at around 60-70% depending on temperature with the result of some crystalline sucrose precipitating out. The majority of sucrose however is converted to the amorphous state, much of which survives the heat drying and milling process. It is due to this reason that the above mentioned techniques make differentiation possible of the chocolate of this invention from commercially available chocolate prepared via a liquid milk process.
The examples which follow illustrate preferred embodiments of the present invention and are not meant to limit the scope of this invention in any way.